#include <stdio.h>

int main()
{
    int a,n,count = 1;
    long int sn = 0,tn = 0;
    printf("please input a and n\n");
    scanf("%d,%d",&a,&n);
    printf("a = %d,n = %d\n",a,n);
    while(count <= n)
    {
        tn = tn + a;
        sn = sn + tn;
        a = a * 10;
        ++count;
    }
    printf("a+aa+aaa+... = %d\n",sn);
}